14,521 research outputs found

    Consonant gemination in Italian: the affricate and fricative case

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    Consonant gemination in Italian affricates and fricatives was investigated, completing the overall study of gemination of Italian consonants. Results of the analysis of other consonant categories, i.e. stops, nasals, and liquids, showed that closure duration for stops and consonant duration for nasals and liquids, form the most salient acoustic cues to gemination. Frequency and energy domain parameters were not significantly affected by gemination in a systematic way for all consonant classes. Results on fricatives and affricates confirmed the above findings, i.e., that the primary acoustic correlate of gemination is durational in nature and corresponds to a lengthened consonant duration for fricative geminates and a lengthened closure duration for affricate geminates. An inverse correlation between consonant and pre-consonant vowel durations was present for both consonant categories, and also for both singleton and geminate word sets when considered separately. This effect was reinforced for combined sets, confirming the hypothesis that a durational compensation between different phonemes may serve to preserve rhythmical structures. Classification tests of single vs. geminate consonants using the durational acoustic cues as classification parameters confirmed their validity, and highlighted peculiarities of the two consonant classes. In particular, a relatively poor classification performance was observed for affricates, which led to refining the analysis by considering dental vs. non-dental affricates in two different sets. Results support the hypothesis that dental affricates, in Italian, may not appear in intervocalic position as singletons but only in their geminate form.Comment: Submitted to Speech Communication. arXiv admin note: substantial text overlap with arXiv:2005.0696

    MoMo: a group mobility model for future generation mobile wireless networks

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    Existing group mobility models were not designed to meet the requirements for accurate simulation of current and future short distance wireless networks scenarios, that need, in particular, accurate, up-to-date informa- tion on the position of each node in the network, combined with a simple and flexible approach to group mobility modeling. A new model for group mobility in wireless networks, named MoMo, is proposed in this paper, based on the combination of a memory-based individual mobility model with a flexible group behavior model. MoMo is capable of accurately describing all mobility scenarios, from individual mobility, in which nodes move inde- pendently one from the other, to tight group mobility, where mobility patterns of different nodes are strictly correlated. A new set of intrinsic properties for a mobility model is proposed and adopted in the analysis and comparison of MoMo with existing models. Next, MoMo is compared with existing group mobility models in a typical 5G network scenario, in which a set of mobile nodes cooperate in the realization of a distributed MIMO link. Results show that MoMo leads to accurate, robust and flexible modeling of mobility of groups of nodes in discrete event simulators, making it suitable for the performance evaluation of networking protocols and resource allocation algorithms in the wide range of network scenarios expected to characterize 5G networks.Comment: 25 pages, 17 figure

    Nanotransporters for the release of bioactive molecules

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    In this project, the nanoformulation of plant extracts in phospholipid vesicles was performed to improve phytochemicals’ applicability in potential skin products. In recent years, the scientific community and pharmaceutical and cosmetic industries gave much attention to plant-derived products with active ingredients. The antioxidant, antibacterial, wound healing, anti-ageing, sun protection, and anti-inflammatory activities are some of their properties highlighted for topical application. Despite this, plant compounds present some drawbacks related to their poor solubility, instability, reduced skin permeation, and low skin retention time, which strongly restrict their topical application. Nanotechnology emerges as an innovative strategy to tackle these limitations: by manipulating materials and reducing their size at the nanometer scale, new structures able to incorporate different active molecules are produced. Nanocarrier-based delivery preserves biomolecules from degradation and increases their bioavailability, at the same time. In this project, the plant material was obtained through alcoholic extractions of different parts of some common plants. Their incorporation in phospholipid vesicles was carried out by a simple sonication of extracts and phospholipids in dispersant solutions. To verify that the nanoformulations had optimal features for skin delivery, a deep characterization was performed, in terms of size, surface charge, sample homogeneity, shape, degree of lamellarity, and entrapment efficiency of the main compounds characteristic of each extract. Their biocompatibility was assayed with different skin cell lines as well as their antioxidant potential. Our results suggest that phospholipid vesicles incorporating plant extracts could be good candidates for topical delivery

    Il medagliere islamico dell'ex museo nazionale di Palermo e la sua collezione inedita di gettoni di vetro

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    In the first part, the essay reconstructs the history and events ofthe two public collections of Islamic coins kept in Sicilian capital: the Medal Cabinet of the former National Museum of Palermo (today A. Salinas Regional Archaeological Museum) and the Nummarium of the Municipal Library, using the information handed down by contemporary historians and especially that derived from the letters exchanged between the Archaeologist A. Salinas, the Numismatist B. Lagumina and the Arabist M. Ainari. The second part of the paper provides a list and a brief description ofthe 90 Islamic glass jetons belonging to the collection of the Archaeological Museum

    Sicilia Aghlabita: Nuove testimonianze numismatiche

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    Questo saggio si propone di illustrare 22 sigilli di piombo di età aghlabita di provenienza siciliana1. Gli esemplari presi in esame, sebbene inediti, afferiscono ad una tipologia già delineata in due studi precedenti dei quali il primo, a firma di P. Balog, risale al 1979 e il secondo, pubblicato da chi scrive, risale al 2003. I sigilli pubblicati dall'autrice, a differenza di quelli illustrati dal Balog e dei nuovi che qui mi accingo ad illustrare, costituiscono il frutto di una campagna di scavo ufficiale condotta nell’area archeologica di Milena (Sicilia: provincia di Caltanissetta) e hanno dunque, rispetto a tutti gli altri, il pregio di provenire da un sito studiato a fondo dagli archeologi, il che – come il lettore si renderà conto presto – avrà importanti refluenze sulla discussione intorno all’uso di questi manufatti

    Cooperative sensing of spectrum opportunities

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    Reliability and availability of sensing information gathered from local spectrum sensing (LSS) by a single Cognitive Radio is strongly affected by the propagation conditions, period of sensing, and geographical position of the device. For this reason, cooperative spectrum sensing (CSS) was largely proposed in order to improve LSS performance by using cooperation between Secondary Users (SUs). The goal of this chapter is to provide a general analysis on CSS for cognitive radio networks (CRNs). Firstly, the theoretical system model for centralized CSS is introduced, together with a preliminary discussion on several fusion rules and operative modes. Moreover, three main aspects of CSS that substantially differentiate the theoretical model from realistic application scenarios are analyzed: (i) the presence of spatiotemporal correlation between decisions by different SUs; (ii) the possible mobility of SUs; and (iii) the nonideality of the control channel between the SUs and the Fusion Center (FC). For each aspect, a possible practical solution for network organization is presented, showing that, in particular for the first two aspects, cluster-based CSS, in which sensing SUs are properly chosen, could mitigate the impact of such realistic assumptions

    Innovative approaches for the diagnosis of Parkinson’s disease and multiple system atrophy based on the analysis of the olfactory mucosa

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    Parkinson's disease (PD) and multiple system atrophy (MSA) are neurodegenerative diseases whose diagnosis is particularly complex, especially in the early stages, because the symptoms are similar to each other and to those of other diseases, including dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). All these disorders share a similar pathological process: the change in the structure of some proteins normally present in the brain which thus lose their function, begin to aggregate and deposit in specific brain areas, causing irreparable damage. In particular, PD, MSA and DLB are called α-synucleinopathies because they present aggregates of the α-synuclein protein (αSynD), which however are localized in different brain structures. PSP and CBD are instead called tauopathies because they are characterized by the presence of aggregates of the tau protein. These protein aggregates are considered disease-specific biomarkers because their detection and distribution (which can only be determined post-mortem on the patient's brain tissue) are used to formulate a definite diagnosis. As long as the patient is alive the diagnosis is only probable and does not have absolute accuracy. Consequently, some diagnoses made in life may change after the neuropathological assessments. Several evidence suggests that misfolded proteins can also appear in peripheral tissues such as the olfactory mucosa (OM, easily and periodically collectible with a nasal swab), but in such small quantities as not to be detectable with common diagnostic techniques. The recent advances in molecular and structural biology have provided insights into the processes involved in the pathogenesis of neurodegenerative diseases and have made it possible to recapitulate the protein misfolding process in vitro in a limited period of time through the development of innovative techniques, called seed amplification assays (SAAs), among which the real-time quaking-induced conversion (RT-QuIC). This new methodology exploits the ability of misfolded proteins to transmit their abnormal conformation to normal monomers, which are used as substrate of the reaction. Abnormally folded proteins are able to interact with these substrates and induce monomers to change conformation and subsequently aggregate. Therefore, the addition of misfolded proteins (considered “seeds”) to the substrate is able to trigger an aggregation phenomenon, known as “seeding effect” that might be exploited for diagnostic and therapeutic purposes. In my Ph.D. project I have firstly optimized the RT-QuIC assay, with the aim of analyzing OM samples collected from patients with PD, MSA, CBD and PSP, and evaluating the efficacy of the test in detecting traces of misfolded αSynD in α-synucleinopathy derived samples. The results of our study showed that most OM samples from patients with PD and MSA induced aggregation of the recombinant substrate protein, suggesting the presence of traces of αSynD. In contrast, the PSP and CBD samples had no effect on the substrate (since they do not contain abnormal αSyn). Interestingly, the RT-QuIC reaction products acquired biochemical and biophysical characteristics useful to discriminate, with a good degree of accuracy, patients with PD from patients with MSA. Moreover, by exposing neuronal-like differentiated SH-SY5Y cells to these products, we observed the induction of different inflammatory pathways. These findings suggested the existence of a link between the morphology of the aggregates and their inflammatory properties. To deepen this aspect, we have produced three different recombinant aggregates of αSyn, in order to generate, in a controlled environment, artificial αSyn seeds resembling to some extent the αSynD strains present in OM, and test their behavior by RT-QuIC without the presence of other tissue factors. Although capable to efficiently seed the aggregation of the substrate, αSv1, αSv2, and αSv3 did not transmit their seed-specific properties to the reaction products which showed comparable biochemical properties, instead. Probably, our experimental setting was too artificial to properly recapitulate the phenomenon of the seeding effect exerted by αSynD in RT-QuIC. However, when used to stimulate SH-SY5Y cells, αSv1, αSv2, and αSv3 acted on different activators of inflammatory pathways, thus strengthening the existence of a correlation between morphological and inflammatory properties of αSyn fibrils. In the last part of my project, we decided to evaluate how much the RT-QuIC assay could be used for diagnostic purposes in the field of α-synucleinopathies, by studying its reproducibility in other laboratories. Together with an American lab we have so analyzed a group of OM samples with the same experimental protocol and we obtained a 96% concordance of results. Furthermore, we observed that the OM of MSA behaved differently according to the pathological subtype. In fact, we know that this disease can manifest itself in a cerebellar form (MSA-C) or associated with parkinsonism (MSA-P). In our test, only MSA-P samples induced a seeding effect, allowing us to discriminate between the two pathological subtypes. These preliminary studies provide evidence that RT-QuIC of OM samples represents a reliable assay for supporting the diagnosis of α-synucleinopathy and may limit the negative effects that misdiagnosis produces in terms of costs for the healthcare system and improve overall patient care, treatment, and possible enrollment in future clinical trials

    Navigational style influences eye movement pattern during exploration and learning of an environmental map

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    During navigation people may adopt three different spatial styles (i.e., Landmark, Route, and Survey). Landmark style (LS) people are able to recall familiar landmarks but cannot combine them with directional information; Route style (RS) people connect landmarks to each other using egocentric information about direction; Survey style (SS) people use a map-like representation of the environment. SS individuals generally navigate better than LS and RS people. Fifty-one college students (20 LS; 17 RS, and 14 SS) took part in the experiment. The spatial cognitive style (SCS) was assessed by means of the SCS test; participants then had to learn a schematic map of a city, and after 5 min had to recall the path depicted on it. During the learning and delayed recall phases, eye-movements were recorded. Our intent was to investigate whether there is a peculiar way to explore an environmental map related to the individual's spatial style. Results support the presence of differences in the strategy used by the three spatial styles for learning the path and its delayed recall. Specifically, LS individuals produced a greater number of fixations of short duration, while the opposite eye movement pattern characterized SS individuals. Moreover, SS individuals showed a more spread and comprehensive explorative pattern of the map, while LS individuals focused their exploration on the path and related targets. RS individuals showed a pattern of exploration at a level of proficiency between LS and SS individuals. We discuss the clinical and anatomical implications of our data

    Sexing up the international

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    This thesis takes sexuality as its subject matter and uses a methodology informed by postcolonial studies to explore new possibilities for thinking about the international, its construction, and its contemporary politics. I argue that postcolonial readings of sexuality can impel us to rethink the meanings and politics of international theory and to challenge notions that have come to appear fixed and unchanging. The thesis canvasses how such an intervention might occur – calling especially for a focus on the local and the everyday – and considers both the utility and the limits of the contributions sexuality might make to a rethinking of international theory. My arguments are made with reference to a series of specific examples from contemporary East and Southeast Asia: the nationalistically imbued gendered and sexed figures of the national serviceman and the Singapore Girl in Singapore; the political and social repercussions of the trial of former Malaysian Deputy Prime Minister Anwar Ibrahim on charges of sodomy; newly emerging homosexual identities in Hong Kong; and the connections between sexuality and disease that inform the Thai response to HIV/AIDS. These case studies exemplify some of the ways in which sexuality can work to recast traditional scholarly understandings of the international. They also illuminate a series of aspects that shape the encounter between sexuality and the international, encompassing issues of nationalism, globalization, metaphor, spatiality and knowledge politics. Through my analysis of these issues, I argue for a broadening out of the source materials that inform knowledge about the international and the pursuit of alternative modes of reading processes of international change and exchange. I contend that scholarship of the international needs to pay more attention to instances where the borders separating everyday, national and international spaces break down, and where we might detect new forms of knowledge about the nature, politics and functioning of the international realm
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